1. Field of the Invention
The present invention relates generally to improvements in hand operated cutting tools and more particularly pertains to new and improved blade assemblies for hand operated cutting tools.
2. Description of Related Art
In the field of hand operated cutting tools, it has been the practice to use standard bypass, hook and blade, and anvil type cutting blades. Significant design effort has been directed to providing mechanisms that connect the handles and blades and reduce the force required on the handles to cause those standard blade arrangements to cut a standard maximum diameter branch.
U.S. Pat. No. 5,469,625, granted on Nov. 28, 1995 to Craig H Melter et al. for a Compound Action Hand Pruner, shows a hand pruner using a force multiplying linkage between a handle and the hook, of a hook and blade arrangement, to provide maximum cutting force between the hook and blade, before the hook and blade actually engage.
U.S. Pat. No. 6,829,829 granted Dec. 14, 2004 to Huang for Gardening Pruner Provided With Means To Effectuate Efficient Transmission Of Force From Handles To Blades Thereof shows a hand pruner using two pivoting plates with gear teeth to engage gear teeth on the two blades. The gear teeth transfer force from the handles to the blades causing enhanced transmission of force from the handles to the blades.
U.S. Pat. No. 6,446,343 granted on Sep. 10, 2002 to Huang for Structure For Improving Efficiency of A Movable Jaw Of A Tree Pruner shows a hand operated tree pruner with a fixed jaw and a movable jaw pivoting with respect to the fixed jaw. The movable jaw is restricted in movement in order to improve cutting efficiency.
U.S. Pat. No. 5,745,998 granted May 5, 1998 to Le et al. for a Pruning Implement, shows a hand operated tree pruner with a hook and blade shearing mechanism wherein the blade pivots with respect to the hook by way of a leverage arm connected to the blade, thereby allegedly reducing the force required to cut the branch.
US published application 2003/0167640 published on Sep. 11, 2003 is an application by Edward Heck et al. for Pruners For Cutting Vegetation. This published application shows a hand operated pruner using a pair of blades mounted to the forward end of a body for relative movement with respect to each other. A lever that is pivotally mounted at the rearward end actuates one of the blades by way of a linkage in the body, thus providing a more efficient application of the cutting force.
It appears that modification of cutting blades arises only in the context of a mechanized cutting implement such as a mechanized tree pruner.
U.S. Pat. No. 5,086,819 granted Feb. 11, 1992 to John Selby for curved tree pruner blades shows the use of multiple concave face blades in a knife belt powered tree pruner in order to provide a closer pruning cut. The present invention requires reduced force to operate a hand operating cutting tool to cut branches having a variety of diameters.